Process and apparatus for the production of bitumens from underground deposits having vertical burning front



July 22, 1969 H. LANGE 3,456,730

PROCESS AND APPARATUS FR THE PRODUCTION OF BITUMENS FROM UNDERGROUNDDEPOSITS HAVING VERTICAL BURNING FRONT Filed. Aug. 22, 1967 2Sheets-Sheet l Fica! :Nl/:Nros HANS LANG:

Muff@ uw@ ATTORNEYS Juy 22, 1969 H. LANGE 3,456,730

PROCESS AND APPARATUS FOR THE PRODUCTION OF BITUMENS FROM UNDERGROUNDDEPOSITS HAVING VERTICAL BURNING FRONT Filed Aug. 22, 1967 2sheets-sheet Sfraum conems d 2; with oxygen-enrich@ Wd, r modif/'ed gasof'cambusfim e FIG. 5

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r., wim modif/@d l r 1 as of [1 I nu cgmbusian E Mw' wafer -I l "-1 INVENTOR HANS LANG:

BY mafffvww ATTORNEYS U.S. Cl. 166--256 11 Claims ABSTRACT OF THEDISCLOSURE In an underground deposit having highly viscous or solidbitumens therein and vertical and inclined borings extending into thedeposit from the surface of the ground, with concentric tubing systemssuch as disclosed in U.S. Patent 3,242,989 installed in the borings, aprocess for obtaining bitumens from the deposits by conducting an insitu combustion in the deposits with an oxygen enriched gas ofcombustion such as disclosed in U.S. Patent application Ser. No.440,852, tiled Mar. 18, 1965, now U.S. Patent No. 3,344,856, theimprovement comprising developing a burning zone with the oxygenenriched gas of combustion at the foot of each installed tubing systemand upwardly along the axis thereof from the lower outlet of theinnermost tube 25 to the successively open inlets of the outer tube 23,diverting and widening the burning front horizontally from the axis ofthe tubing system, sometimes with reversal of the burning and flowdirections of the individual bores, and after suicient heating withliquefaction of the stratum contents and vaporization thereof with steamfrom water injected to the intermediate tube 24 and, producing thestratum contents from all the borings.

CROSS-REFERENCES TO lRELATED APPLICATIONS Applicant claims priorityunder 35 U.S.C. 119 for the patent application Ser. No. D 51,652, tiledNov. 26, 1966, in the Patent Ofce of the Federal Republic of Germany.

Applicant refers to the U.S. patent application of Hans Lange,application Ser. No. 440,852, filed Mar. 18, 1965, now U.S. Patent No.3,344,856, which in turn is a continuation-in-part of U.S. patentapplication Ser. No. 349,589, filed Mar. 5, 1964, now U.S. Patent No.3,360,044. The application of Gunther Schlicht and Hans Lange, U.S.application Ser. No. 489,776, led Aug. 9, 1965, now U.S. Patent No.3,349,850, which in turn is a division of application Ser. No. 215,494,filed Aug. 6, 1962, now U.S. Patent 3,242,989, dated Mar. 29, 1966, isalso referred to.

BACKGROUND OF THE INVENTION The eld of the invention is broadly wellsand processes for introducing heat and lluid thereto. Wells having belowand above ground modification are also included in the field of theinvention.

In order to obtain highly viscous, congealed solid bitumens fromunderground deposits, it has been suggested, among other procedures, toperform an in situ combustion of certain components of an undergrounddeposit with a burning front established in the deposit so as to meltand/ or vaporize the components ahead of the burning front, whereby thecomponents are brought above ground in the liquid or gaseous state.

According to U.S. Patent 3,344,856, supra, an in situ ice combustion forunderground deposits is described in which a gas of combustion having agiven composition is mixed with Slt-% oxygen to serve as a heat carryingmedium and also as an oxidizing agent for supporting an in situcombustion of hydrocarbons in the underground deposit. An importantcharacteristic of the gas of combustion which is introduced into thedeposit from above ground, or is formed by in situ combustionunderground, is that its components are completely soluble in theunderground deposit. The components of the gas of combustion are carbondioxide and steam and only small amounts of nitrogen. These componentsof the gas of combustion give their heat contents to the undergroundmedium, such as to the liquefied and vaporized carbon contents, so as toprovide a source of heat which, except for the added oxygen, is composedentirely of substances from the deposit.

The process for the recovery of liquid and solid bitumens fromunderground deposits disclosed in U.S. Patent 3,344,856 comprises thefollowing steps:

(a) Locating at least one relatively deep flooding boring, at least onerelatively shallow production boring, and at least one treatment boring,and at least one leading boring, said treatment and leading boringslocated between said ooding boring and said production boring in aspaced predetermined direction apart from one another in the stratum ofan underground deposit of bitumens;

(b) Introducing into said treatment boring an activated gas ofcombustion comprising oxygen and hot modified gas of combustioncomprising steam and carbon dioxide;

(c) Developing a hot reaction zone between at least one of saidtreatment borings and at least one of said leading borings having agiven temperature range by the sensible heat of said gas of combustionand the reaction of a portion of said bitumens and hot oxygen andproducing additional modied gases of combustion;

(d) Conducting further into said stratum ahead of said reaction zonesaid additional modied gases of combustion from (c), where they condenseand dissolve to form a liquid phase with contents of the stratum; and

(e) Advancing said reaction zone and displacing ahead of it stratumcontents of condensed and dissolved gas of combustion in the directionof the production boring by the introduction of water to said floodboring, and removing the advanced stratum contents through theproduction boring.

In U.S. Paatent 3,242,989, an apparatus is disclosed for heatingunderground deposits by the use of a heat source in the form of anuclear reactor that is positioned in the borehole for heat carryingmedium which is pumped in a vertical and horizontally expanding pathbetween the deposit and the boring. The apparatus according to U.S.Patent 3,242,989 comprises: a Center casing and a pair of inner andouter concentric tubular casings extending into an undergroundbituminous deposit with said inner casing being rotatable, meansdefining a plurality of passages vertically spaced in said outer casingand staggeredly positioned thereon, rotary valve means actuated by saidinner casing for selectively opening and closing said passages, apermeable layer of solid material on the lower end of the outer surfaceof said outer casing and extending over about one-third of the height ofthe deposit, and a pump connected in fluid communication with saidouter, inner and center casings for circulating a liquid therethrough.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to avoid the limitations of and to improve the efficiency ofprior art processes.

Another object of the present invention is an improved process forcarrying out an in situ combustion in the stratum of a bituminousdeposit.

Another object of the invention is an improved apparatus for carryingout the in situ process in the stratum of bituminous deposits.

A particular object of the present invention is to provide an in situcombustion process in the stratum of a bituminous deposit having avertical burning front.

Upon further study of the specification, drawings and claims otherobjects and advantages of the present invention will become apparent.

According to the present invention, an in situ combustion of a heatcarrying medium consisting of a stratum component which has beenenriched with oxygen is used as a source of heat and energy accordingto` the disclosure of U.S. Patent 3,344,856, supra, and a nuclearreactor is not necessary as a heat source.

The present invention combines a vertical circulation process with an insitu combustion and renders the reactor superfluous. By means of asource of heat energy that is produced directly in the stratum, from thestratum contents and oxygen, and is circulated throughout the stratum,the combination offers the possibility, even in a deposit of smallyield, to render the stratum productive and to exploit the same.

The in situ combustion, which is used as a source of heat energy, isperformed in the region of vertical and inclined borings where the upperand the lower ends of the borings are brought alternatively to within agiven distance from each other.

At least one, and preferably a row of vertical and inclined borings areextracted from the surface of the ground into the stratum of thebituminous deposit. Into the borings are inserted an apparatuscomprising three concentric casings. The innermost casing hasconnections for delivering modified gas of combustion enriched withoxygen from the surface to the stratum. The intermediate casing hasmeans for delivering water or steam to the stratum. Mounted on theintermediate casing are rotary or longitudinally shiftable valves whichcooperate with openings or inlets in the outermost casing.

The process is begun by injecting gas of combustion enriched with oxygeninto the stratum through one or more of the inclined and verticalborings. The oxygen enriched gas of combustion is ignited and thestratum contents are heated to a Huid state. The inlet valves in theoutermost casing are opened and the fluid stratum contents are broughtto the surface for circulation and return through the innermost casingto the stratum. The burning front is advanced vertically along the axisof the outermost casing by subsequently opening the valve further up onthe casing. As the burning fronts of adjacent borings expand verticallyand horizontally, they connect with one another and it is then possibleto carry out an in situ combustion between adjacent borings.

BRIEF DESCRIPTION OF THE DRAWINGS The process and apparatus of thepresent invention may be further explained by reference to the attacheddrawings wherein:

FIGURE l is a plan view of alternately vertical and inclined boringsinserted from the surface of the ground into the stratum of a bituminousdeposit;

FIGURE 2 is a vertical section of the stratum in the plane of theborings of FIGURE 1;

FIGURE 3 is a more detailed showing of the apparatus used in FIGURE 2;

FIGURE 4 is a detailed showing of a vertical component of the apparatusof FIGURE 3 in which the valves are longitudinally adjustable; and

FIGURE 5 is a detailed showing of a vertical component of the apparatusof FIGURE 3 in which the valves are rotatably adjustable.

With particular reference to FIGURES l and 2, vertical borings 0, 2, 4,6 and 8 and inclined borings 1, 3, 5

Cit

and 7 are shown extending from the surface of the ground through uppercover rock 1t) into the deposits having lower cover rock 1l. The symbolX designates the foot of the inclined and vertical borings.

FIGURE 3 illustrates the use of an apparatus generally similar to thatdisclosed in U.S. Patent 3,242,989, applied to the method of the presentinvention. The apparatus is inserted into inclined borings 5 and 7having vertical borings 6 intermediate thereto. Each apparatus comprisesthree coaxial tubes 23, 24 and 2S. The outermost tube 23 is surroundedby a permeable material 27 in the lower third of the productive portionof the deposit, down to the lower end of the tube. The outermost tube isalso provided at successive higher levels with circumferentiallystaggered openings which are closed or opened successively in the upwardor downward direction by rotary valves 30, 31 and 32 on the middletubing 24. These openings can, however, also be opened or closed bymovement of the middlel tubing in the axial direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The process of this inventionis characterized in that a burning zone 50, as shown in FIGURE 3, isestablished by the oxygen enriched gas of combustion in the individualborings of a section of the stratum at the foot of the tubing systembetween the lowermost opening of the inner tube 25 and the successivelyopened outlets along the length of the outer tube 23. By theintroduction of water througr the middle tubing 24 and out of the loweropening at 28, the burning zone is diverted and widened, sometimes witha reversal of the direction of burning in the stratum and of flow in theindividual tubings, so that after sufficient heating of the deposits andliquefaction of their contents, the latter can with the help offlash-vaporization of the steam 4from the injected water, be broughtthrough the various borings to the surface.

As stated above, the burning zone which is formed around the tubingsystem of a boring can be diverted and widened in the horizontaldirection. This is effected by the introduction of water through thepermanently open passageways at 28 in the horizontal direction betweenthe inlet and outlet openings of the tubings. The water forces theburning zone away from the borehole axis into the neighboring parts ofthe stratum while the resulting hot steam, besides its direct heatingeffect, also causes ilash vaporization of voltaile components of thedeposit which escapes to the surface through inlet openings of thetubing system. A permeable layer around the tubular system in the lowerportion of the deposit is established by making the boring in thisregion of larger diameter and lling the resulting intermediate space-between the wall of the boring and the casing with porous sand.

It has been found advantageous to enclose a section of the deposit byrows of borings in which the individual boreholes are alternatelyvertical, as at 0, 2, 4, `6 and 8, and inclined, as at 1, 3, 5 and 7. Asis shown in the drawings, the tubings in adjacent borings are in closeproximity to each other alternatively at the rock formation above, or atthe formation below the deposit. The minimum distance between adjacentborings is determined lby the kind of rock, and can be from l0 to 100meters. In homogeneous rock formations, minimum spacings of 30 to 5()meters have been found advantageous. After the formation of a burningzone around each boring and gradual warming of the stratum in theregions between adjacent borings, production is obtained through all theborings.

The heating of the intermediate regions by heat conduction laterallyfrom the heat carrier into the deposit results from the greattemperature difference between the relatively hot heat carrier flowingupwardly from the burning zone to the head of the boring, and therelatively cool intermediate regions. In this manner large amounts ofheat are conducted across these short paths into the intermediateregions without any movement of the stratum contents.

After the temperature of the products in the deposit has been raised tothe boiling point of water under the existing pressure conditions, theinclined borings are used as injection borings for the oxygen-enrichedgas of combustion. The gas is delivered at the foot of the inclinedboring from the innermost tube 25 into the deposit. The removal of theliquefled and vaporized stratum contents is accomplished in a controlledmanner by the vertical borings where the iluidized material enterssuccessively through the uppermost openings of the outermost tubes 23.To reach all portions of the deposit and to prevent the formation ofparticular flow channels, the direction of flow through certain boringsmay be reversed.

Under particular operating conditions, when the temperature of theproduct reaches the temperature of boiling water, all the borings ofthat portion of the deposit are operated as injection borings and only asingle vertical boring near the center of the deposit is operated as aproduction boring. The gas of combustion after its enrichment with anoxygen carrier is introduced in graduated amounts through the innermosttu'be 25, namely through the lowest opening. Here also the medium onoccasions is introduced alternately through this lowermost opening orthrough an upper opening of the outer tube 23.

After sufllcient warming of the section of the deposit that is enclosedby the borings and after diminished production, water is introduced asooding water through the lower openings of the tubing systems of allborings and becomes successively warmed through the liberated hot oil.The water is introduced into the deposit to displace the stratumcontents toward the upper portion of the deposit for delivery throughthe openings in the upper portion of the tubing system 23 to thesurface, first through the lowermost openings and then through openingsat higher levels 30-32 as the level of the water rises.

With only slight differences, the tubing system used here corresponds tothe tubing system of U.S. Patent 3,242,989 for bitumen production.Without the use of an atomic reactor as a stationary source of heat, andwith the production of the required heat by in situ combustion toproduce a movable source of heat externally of the apparatus, the oxygenenriched gas of combustion is introduced through the innermost tube 25into the deposit where it is returned through the various openings inthe outermost tube 23 to above ground. A portion of this product in theform of an inert gas of combustion, is then again enriched with oxygenand returned through the innermost tube 25 for recirculation through thedeosit.

p After a burning front has been formed in the immediate neighborhood ofthe boring, water is continually introduced through the middle tube 24and the communicating openings at 28 in the outer tube 23 for injectioninto the burning front to drive it out and widen it horizontally. Thesteam which is formed in the hot burning front causes some flashvaporization of the stratum contents. The intermediate tubing 24 whichis rotatable or movable vertically is closed at its lower end. Itreceives the water from a separate conduit. Its coordination with theoutlet openings of the surrounding outer tube 23 is such that there isuninterrupted injection of water into the stratum.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions. Consequently, such change and modifications are properly,equitably, and intended to be, within the full range of equivalence ofthe following claims.

I claim:

1. In an underground deposit having highly viscous or solid bitumenstherein and borings having vertical and inclined axes extending into thedeposit from the surface of the ground, tubing systems installed in saidborings comprising first, second and third concentric tubes wherein saidfirst tube is the outer tube and has openings in the surface thereof,said second tube is the intermediate tube and has rotating valvesaffixed thereto cooperating with said openings and said third tube isthe innermost tube with an outlet at the bottom thereof, a process forobtaining bitumens from the deposits by conducting an in situ combustionin the deposits with an oxygen enriched gas of combustion, theimprovement comprising;

(a) developing a burning zone with the oxygen enriched gas of combustionat the foot of each installed tubing system and upwardly along the axisthereof from the lower outlet of the innermost tube;

(b) diverting and widening the burning front horizontally from the axesof the tubing systems in the borings;

(c) after heating of the stratum contents, introduction of water intothe middle tubing whose lower end is closed and expulsion of said waterthrough the continually open lowermost valve, liquefaction and flashvaporization ahead of the burning zone by the steam that is formed byvaporization of the expelled water, and removal of the liquefied andfurther heated bitumens through upper openings of all the borings,beginning with the lowermost opening of the three superimposed rotaryvalves; and

(d) widening and expanding the horizontal reaches of the flowing hotstratum contents and of the burning front by closure of the loweropening and by opening the middle rotary valve, and after furtherexpansion of the horizontal warming front by closing the middle rotaryvalve and instead opening the upper rotary valve.

2. The process of claim 1, wherein the burning and flow directions ofthe individual borings are reversed.

3. The process of claim 1, characterized in that upon reaching theboiling point of the water under the existing pressure conditions in thedeposit the stratum contents are ilashed, the inclined borings are thenused only as injection borings for the oxygen enriched combustion gasand the vertical borings only as production borings for the liquefiedand flash steam treated stratum contents, whereby the oxygen enrichedcombustion gas is introduced at the feet of the inclined borings and thestratum contents delivered through the successively opened upperopenings to above ground.

4. The process of claim 3, wherein the direction of flow is reversed.

5. The process of claim 1, characterized in that progressively with theincreased warming of the stratum, the stratum conte-nts are delivered inthe specified manner only by a single vertical 'boring at the center ofthe deposit that is being exploited, and oxygen enriched gas ofcornbustion is injected in measured amounts into the stratum at the feetof all the remaining vertical and inclined borings.

6. The process of claim 5, wherein said oxygen enriched gas ofcombustion is injected alternately through the lower and upper openingsin the tubing systems of the remaining borings.

7. The process of claim 1, characterized in that in a last phase of theprocess the injection of enriched oxygen into the borings is stopped,and that by floating with water that has become heated after itsinjection from the feet of all borings, the liquefied stratum contentsare displaced for delivery through the successively opened inletopenings in the upper portions of all borings to above ground.

8. The process of claim 7, wherein said stratum contents areprogressively removed through openings at higher levels in said tubingsystems as the water level rises.

9. An apparatus for obtaining bitumens from an underground deposithaving highly viscous or solid bitumens, said apparatus comprising a rsttube (23) in the form of an outer casing with selectively controlledlongitudinally spaced openings at different levels and a permanentlyopen water outlet passageway (28) at a lower level, a second tube (24)carrying longitudinally spaced valves (30), (31) and (32) and movablerelative to the first tube to selectively control the longitudinallyspaced openings and also providing a permanently open passage- Way forWater from the interior of the second tube and through the permanentlyopen passageway (28) to the stratum, a third tube (25) coaxial with theiirst and second tubes and forming a uid-tight fit with the lower end ofthe second tube, a permeable covering over the water outlet passageway(28) extending around the outside of the tirst tube, and means forconducting an oxygen-containing gas from above ground to the upper endof the third tube.

10. The apparatus of claim 9, in which the movement of the second tuberelative to the tirst tube to selectively control the longitudinallyspaced openings is a rotary movement.

11. The apparatus of claim 9 in which the movement of References CitedUNITED STATES PATENTS 3,024,013 3/1962 Rogers et al. 166-11 3,044,5467/1962 Dixon 166--11 3,055,423 9/1962 Parker 166-11 3,057,404 10/1962Bergstrom 166-52 X 3,242,989 3/1966 Schlicht et al. 166-52 3,344,85610/1967 Lange 166-11 X 3,360,044 l2/1967 Lange 16S-1l STEPHEN I.NovosAD, Primary Examiner U.S. C1. XR.

